static_assert( __cplusplus > 2020'99 );

#pragma once

#include <Alepha/Alepha.h>

#include <memory>

namespace Alepha::Hydrogen::Utility  ::detail::  derived_pointer_cast_m
{
	inline namespace exports
	{
		template< typename Target, typename Source >
		std::unique_ptr< Target > derived_pointer_cast( std::unique_ptr< Source > source );
	}

	template< typename Target, typename Source >
	std::unique_ptr< Target >
	exports::derived_pointer_cast( std::unique_ptr< Source > source )
	{
		if( Target *const conv= dynamic_cast< Target * >( source.get() ); not conv )
		{
			// TODO: More precise Alepha exception here.
			throw std::bad_cast{};
		}
		else
		{
			// It's safe to release here, because we're taking ownership below.
			source.release();

			// We reuse the conversion pointer so we can avoid a double-trip thru the
			// RTTI pathway.
			return std::unique_ptr< Target >{ conv };
		}
	}
}

namespace Alepha::Hydrogen::Utility::inline exports::inline derived_pointer_cast_m
{
	using namespace detail::derived_pointer_cast_m::exports;
}